Computed Tomographic Evaluation of Adjacent Segment Motion after Ex Vivo Fusion of Equine Third and Fourth Cervical Vertebrae.

The research paper investigates the impact surgical fusion of vertebral segments has on adjacent vertebral sections in horses, focusing on the range of motion before and after the procedure. The study found that intervertebral fusion did not significantly alter the range of motion in the examined segments.

Overview of the Research

• The study was conducted on cervical (neck) specimens from 12 horses. The Range of Motion (ROM), which refers to the maximum amount a joint can move in different directions, was measured between the second and fifth cervical vertebrae. This was done using computed tomographic (CT) imaging, a type of specialized X-ray technology that creates detailed images of the body.
• The third and fourth cervical vertebrae (C3/4) were fused, using standard locking compression plate and locking head screws, to stabilize the neck possibly due to cervical stenotic myelopathy or fracture. After the fusion, CT scans and ROM measurements were conducted again.

Research Findings

• Prior to the intervertebral fusion, researchers noticed a significant increase in ROM from cranial (head end) to caudal (tail end) along the vertebral segments. This may indicate a natural difference in mobility in these segments.
• Notably, the motion range of the fused third and fourth vertebrae significantly decreased after the procedure, which is expected due to the natural effects of a surgical fusion.
• However, the ROM of the adjacent segments (C2/3 and C4/5) did not change significantly after the fusion. This is a key finding as it implies the fusion operation does not negatively impact the motion of the surrounding vertebrae.

Conclusions and Future Work

• This study concludes that the fusion of one cervical intervertebral joint in horses does not significantly affect the ROM of the adjacent vertebral segments. This indicates that concerns about degenerative diseases due to surgery-related changes in adjacent segments may not be founded.
• However, the authors emphasize that the research does not account for intervertebral pressure or long-term effects post-surgery, which may have different outcomes. Therefore, further research is suggested to explore these variables in the equine patient.